1. Technical Field
The present invention relates generally to a mechanoelectric converter, and more particularly, to a weighing device designed to convert mechanical loads into electric signals using a ceramic shear beam load cell.
2. Related Art
Heretofore, strain gage load cells used in scales for weighing applications consisted of a complex detection circuit made of resistors, which were mounted on the surface of a solid metal substrate. Referring to FIG. 1, a prior art strain gage load cell 10 is shown. In this device, a complex thin film or metal foil strain gage circuit 14 is mounted, typically by a glueing process, to a metal substrate 12, such as stainless steel or aluminum. Load cell 10 is mounted to a base (not shown) via through-holes 16.
FIG. 2 depicts another type of prior art strain gage load cell used in the industry. In this version, substrate 12 is hollowed out at midsection 18 in order to focus the stress in the area where the strain gage circuit 14 is mounted, thereby increasing the sensitivity accuracy of the device.
However, the machining associated with constructing strain gage load cells in either manner is quite costly. This may be partially attributed to the inherent cost of machining a substrate made of stainless steel.
Another costly disadvantage to the current methods used in the industry is the attachment process. Although gluing the strain gages to the surface of the substrate has recently become a reliable means of attachment, the expense remains high.
Based on the above, there exists a need to provide an accurate weighing device that is easier and less costly to produce.